Permutation locks



Dec. 31, 1968 c. A. VAHLSTROM PERMUTATION LOCKS Filed June 13, 1966 CARLA. VAHLSTROM ATTORNEYS United States Patent 3,419,893 PERMUTATION LOCKSCarl A. Vahlstrom, New Britain, Conn., assignor to Emhart Corporation,Bloomfield, C0nn., a corporation of Connecticut Filed June 13, 1966,Ser. No. 556,962 7 Claims. (Cl. 70-24) ABSTRACT OF THE DISCLOSURE A lockstructure in which a fulcrumed blocking lever is provided which uponpivotal movement in a first direction prevents disengagement of a locksecuring element from a lock body. The blocking lever is pivoted on apivot means intermediate its ends which is releasable from a pivotmounting in the lock body. The blocking means of said lever is on oneside of the pivot means and a locking means engages the lever on theopposite side of said pivot means. A single spring engages the blockinglever between the pivot means and the locking means, this single springmeans performing the multiple functions of biasing said lever in asecond direction out of blocking engagement, biasing said pivot meansagainst its mounting with a relatively strong force, and biasing saidblocking lever against said locking means with a relatively light force.

This invention relates to improvements in the permutation lock shown anddescribed in my US. Patent No. 2,853,868.

In that particular permutation lock, two separate and distinct springmeans were required to keep the blocking lever in position relative toits fulcrums in the lock case and to bias the blocking lever out ofengagement with the shackle locking bolts and into engagement with thecontrol discs. The first spring means was a leaf spring which waspositioned between the casing of the lock and the blocking leverdirectly over the fulcrum points for the latter element. The secondspring means was a torsion spring wound about a shaft and acting betweenthe rear wall of the case and the edge portion of a special aperture inthe blocking lever through which the spring extended to urge theblocking lever against the control discs and out of engagement with thelocking bolts. Aside from the number of parts involved, one of theprincipal disadvantages of this combination, and of most otherpermutation locks having'such spring means to bias the blocking leveragainst the fulcrum points in the relative ease with which unauthorizedpersons can open the lock through the well-known process of rapping.Also, since the moment arm through which the second spring acts isrelatively large, the pressure of the blocking lever against thepermutation wheels is relatively great and unscrupulous personsattempting to open the lock can feel the change that takes place in theresistance to the turning movement of the wheels when the combinationhas been set.

The present invention overcomes this and other disadvantages of my priorpermutation lock by providing spring means which urge the blocking leveragainst the control discs with relatively light force, yet holds theblocking lever against its fulcrum points with a relatively large force,thus making unauthorized opening of the look by feel or rappingvirtually impossible.

My improved device does away with the need for separate spring means toretain the blocking lever in operative position and for biasing theblocking lever into engagement with the control discs and out ofengagement with the shackle locking bolts. I accomplish this dual resultby means of a single, conical, compression spring positioned between thecasing of the lock and the blocking lever.

3,419,893 Patented Dec. 31, 1968 My improved device, because it takesthe place of two spring means, while retaining the function of both,makes the permutation locks wherein it is found less expensive andeasier to manufacture. Also, because there is one less spring, there isless likelihood of mechanical failure.

Further, because my improved device uses a conicalshaped coil spring,with the base of the cone bearing against the inside of the lock case, agreater force is placed on the blocking lever at the point of contactbetween the spring and the blocking lever than if any other type ofspring were used. This greater force per unit of spring lengthconcentrated at a particular point on the blocking lever allows forgreater efficiency and maximum utilization of the potential energy ofthe spring.

Therefore, the primary object of my invention is to provide improvedlocking means wherein only one spring means is required to position andactuate the blocking lever through its cycle of operation.

A further object of this invention is to provide an improved springmeans for a permutation padlock which will prevent the opening of saidlock by unauthorized persons not having knowledge of the combination andattempting to open the padlock by feel or by rapping.

Further advantages and objects will become readily apparent from thefollowing description and accompanying drawings wherein:

FIG. 1 is a perspective view of a permutation padlock having therein theimproved mechanism.

FIG. 2 is a sectional front elevational view of the improved padlockwith a portion of the lock case removed to reveal the working mechanism.

FIG. 3 is a sectional side elevational view taken along the line 33 ofFIG. 2.

FIG. 4 is a sectional plan view taken along the line 4-4 of FIG. 2.

FIG. 5 shows a modification of the improved blocking lever.

FIG. 6 shows another modification of the improved blocking lever.

Referring to the drawings in detail, wherein like numerals indicate likeelements, there is shown the case 1 of a padlock having operativelyconnected thereto a securing element in the form of a shackle 2 that isbiased toward unlocked or open position by means of a spring 3.

The shackle locking means embodied in the instant invention includes apair of oppositely disposed locking bolts 4, 5 which are biased inopposite directions by a spring 6 positioned therebetween and retainedon a pin 7, into oppositely disposed notches 8, 8a in the legs of theshackle 2.

The control mechanism for said locking bolts is preferably of thepermutation type and is supported by a frame 9 which is received incavity 10 of the case of the padlock 1. Said frame 9 is secured to saidcase 1 by means of a blind rivet 11.

The permutation mechanism includes a plurality of permutation wheels 12carried on a shaft 13, said shaft being longitudinally shiftable inbearings 14, 15 in the frame 9. The shaft carries a disc 17 which isaffixed to one end thereof outside of said frame 9 and is urged towardthe normal position by means of a spring 16 wound around said shaft andacting between the disc 17 and the outside wall of the frame 9. Each ofthe wheels 12 is operatively engaged with a lock controlling element 18in the form of a disc which is rotatably mounted on the shaft 13 and iscut away at one side thereof to provide a fiat surface 18a on theperiphery of said disc. For proper operation of a device of this type,it is imperative to provide means for holding the permutation wheels 12in set position. For this purpose, a series of notches are cut on theperiphery of each of the permutation wheels and a series of springmembers 19, one for each permutation wheel, are mounted on the wall ofthe frame 9 and are biased into the individual notches as thepermutation wheels are turned.

A blocking lever 20 having a pair of control disc engaging fingers 22and a blocking finger 25 is pivotally mounted intermediate its ends onside walls 21, 21 of the frame 9. The fingers 22 extend between thepermutation wheels 12 and are disposed immediately adjacent the controldiscs 18. The blocking finger 25 is insertable between the ends of thelocking bolts 4, (see FIG. 4) to retain said bolts in locking positionin the notches 8, 8a. The blocking lever 20 is retained in operativeposition and is actuated by a single, conical-shaped, coiled compressionspring 23. The spring 23 is disposed between the Wall of the cavity inthe padlock case 1 and the blocking lever 20. In the embodiment shown inFIG. 3, the base of the conical-shaped spring 23 merely rests againstthe wall of the cavity 10 while the apex of the spring is seated in aspecially designed cup 24 mounted in a hole in said blocking lever 20.In the embodiment shown in FIG. 4, a seat 32 for the base portion of thespring is cut into the wall of the cavity 10 to positively locate thespring.

FIG. 5 shows a modified securing means for retaining the conical-shapedspring in operative engagement with the blocking lever A recess 27 ispunched into the blocking lever 20' and the apex of the spring 23 isdirectly inserted therein when the improved padlock is assembled.

In FIG. 6 a further modification is shown for retaining the spring 23 inoperative engagement with the blocking lever 20". Here a stud 28 isformed on the blocking lever 20", and when the improved padlock isassembled the apex of the coil spring is inserted over said stud.

At one side of the blocking lever 20 there is provided an arcuatelycurved extension 26 which is disposed in the space between the disc 17and the side of the case 9 and which is designed to enter that space andprevent movement of the shaft 13 when the blocking lever is in lockedcondition.

The operation of the improved permutation lock mechanism is as follows:

When the mechanism is in locked position, the blocking lever 20 is heldby the compression spring 23 in contact with the control discs 18, sothat blocking finger of said lever is positioned between the lockingbolts 4, 5 and interferes with the inward movement of said locking boltsout of the notches 8, 8a in the shackle 2 thereby retaining the shacklein locked position. It will be evident that any attempt to pull theshackle 2 outwardly while the locking bolts 4, 5 are engaged in notches8, 8a, will tend to cam said locking bolts into tighter engagement withthe finger 25.

When it is desired to unlock the shackle 2, the control discs 18 areproperly positioned by rotating their respective permutation wheels 12until the proper combination appears on said wheels. All of the fiatsides of the control discs will then be aligned and will be adjacent tothe cooperating fingers 2222 at the lower end of the blocking lever 20.The shackle is then depressed to permit the locking bolts 4 and 5 tomove apart under the influence of the spring 6 and out of interlockingengagement with the blocking finger 25, whereupon the spring 23 willforce the end of the blocking lever inwardly and pivot it about itsfulcrums 21-21 to swing the blocking finger 25 outwardly from betweenthe locking bolts 4, 5. When the shackle is released, it is projectedinto unlocked or open position by the spring 3 which is designed toovercome the force exerted by the spring 6.

When it is desired to lock the said mechanism, either of the two methodsmay be used. In the first method the permutation wheels 12 are rotatedto the proper preselected combination. This causes a correspondingmovement of the control discs 18 bringing all the flat surfaces 18::into alignment immediately adjacent the fingers 22 of blocking lever 20.As the last of the permutation wheels are rotated to bring all the flatsurfaces 18a of the discs 18 into alignment, spring 23 pivots blockinglever 20 about its fulcrum 2121 to move blocking finger 25 outwardly,away from locking bolts 4, 5. Locking bolt 4 is then biased outwardlyunder the influence of spring 6 into the shackle receiving shaft 29;locking bolt 5 is retained in position by surface 31 of shackle 2pressing up against the nose portion 30. The shackle 2 is then moveddownwardly to telescope the shackle into the locking mechanism. Lockingbolt 4 will first be cammed back out of shaft 29 as the shackle descendsthereby compressing spring 6, the bolt will then snap into notch 8 underthe biasing action of spring 6 as notch 8 comes into position. Lockingbolt 5 will snap into notch 8a also under the biasing action of spring 6as notch 8a comes into position. The permutation wheels are thenarbitrarily rotated. This causes the discs 18 to correspondingly rotate,bringing the arcuate surfaces to bear against the blocking lever 22. Theresultant camming action urges the blocking lever to pivot about itsfulcrums 2121 and moves the blocking finger 25 into engagement withlooking bolts 4, 5 to prevent them from moving out of engagement withnotches 8, 8a thereby securing the shackle 2 in the lock mechanism andpreventing its removal.

In the second method the permutation wheels are rotated to any numbercombination while the shackle is outside the lock mechanism. Therotation of the permutation wheels causes a corresponding rotation ofthe control discs 18 bringing the arcuate surfaces to bear on theblocking lever fingers 22. The resultant camming action caused by thespring 23 and the arcuate surfaces of control discs 18 urges blockinglever 20 toward locking bolts 4, 5. Locking bolt 5, because of itsengagement with surface 31 of shackle 2, blocks the path of blockinglever 20. This causes blocking lever 20 to be lifted off its fulcrum2121 and into pressing engagement with locking bolt 5. As the shackle 2descends and the notches 8, 8a align themselves with locking bolts 4, 5the pressure of blocking lever 20 and spring 6 urges the locking bolts4, 5 into engagement with the notches 8, 8a and locks them in position,thereby securing the shackle 2 in the lock mechanism and preventing itsremoval.

What is claimed is:

1. In a locking device, the combination comprising a lock body;

a securing element movablelinto and out of engagement with said body;

a pivotal mounting in said body;

a blocking lever releasably but pivotally mounted thereon in said bodyon a pivot means intermediate its ends, said blocking lever having meanson one side of said pivot means which upon pivotal movement of saidblocking lever in a first direction will prevent disengagement of saidsecuring element from said lock body;

a locking means immediately adjacent said blocking lever on the oppositeside of said pivot means for moving and holding said blocking lever insaid first direction of pivotal movement; and

a single spring means engaging said blocking lever between said pivotmeans and said locking means, said spring means exerting a bias on saidlever in a direction to normally hold said releasable pivot means onsaid mounting and to urge said blocking lever in a second direction ofpivotal movement opposite to said first direction; said single springmeans holding said lever on said pivotal mounting with a relativelystrong force, and biasing said blocking member against said lockingmeans with a relatively light force.

2. The locking device as defined in claim 1 wherein said lock body hasat least one spring urged locking bolt to operatively engage saidsecuring element when said securing element is in engagement with saidlock body, said blocking lever operatively engaging said locking boltwhen said lever is pivotally moved in said first direction to preventretracting movement of said locking bolt and thereby preventdisengagement of said securing element from said lock body.

3. The locking device defined in claim 1 wherein said single springmeans comprises a helical compression spring biased between a portion ofsaid lock body and said blocking lever; and means to retain said springin operative position between said blocking lever and said portion ofsaid lock body.

4. The locking device defined in claim 1 wherein said single springmeans comprises a conically shaped, coiled compression spring biasedbetween a portion of said lock body and said blocking lever, and meansto retain said spring in operative position between said blocking leverand said portion of said lock body.

5. The locking device defined in claim 3 wherein said last mentionedretaining means comprises a recess cut in said blocking lever and a cupinserted in said recess, said helical spring being accepted directlyinto said cup when said locking device is in assembled relationship.

6. The locking device defined in claim 3 wherein said last mentionedretaining means comprises a cup-shaped recess formed in said blockinglever, said helical spring being accepted directly into said cup-shapedrecess when said blocking lever is positioned in said lock body.

7. The locking device defined in claim 3 wherein said last mentionedretaining means comprises a pin formed on said blocking lever, saidspring being accepted on said pin when said locking device is inassembled relationship.

References Cited UNITED STATES PATENTS 2,114,073 4/1938 Denerich -252,183,168 12/1939 Pond 70-25 2,183,792 12/1939 Eden 70-25 2,853,8689/1958 Vahlstrorn 70-24 MARVIN A. CHAMPION, Primary Examiner.

EDWARD J. MCCARTHY, Assistant Examiner.

Disclaimer 3,419,893.-0(17Z A. Vahlstrmn, New Britain, Conn. PERMUTATIONLOCKS. Patent dated Dec. 31, 1968. Disclaimer filed Feb. 23, 1977, bythe assignee, E'mhart Industries, Inc. Hereby enters this disclaimer toclaims 1, 2, 3 and 7 of said patent.

[Ofiicial Gazette May 3, 1.977.]

